NBC has won its third straight Monday in key demos on the strength of a dominant performance by “The Voice,” but the net is getting less help from “Smash,” which lost another half a ratings point in its third outing and placed third in its second half-hour.

According to preliminary national estimates from Nielsen, “The Voice” was again easily Monday’s top-rated program in both adults 18-49 (5.8 rating/14 share) and total viewers (15.7 million). It beat runner-up CBS by 53% in 18-49 rating (5.8 vs. 3.8) and outperformed its third-week score of last season by a hefty 23% (5.8 vs. 4.7).

Not looking as good was the third week of Broadway-themed drama “Smash” (2.3/6 in 18-49, 6.5 million viewers overall), which was down from the 2.8 demo score it had last week when it narrowly led the hour in the demo; this time around, though, it placed second for the hour to CBS’ “Hawaii Five-0” (2.8/7 in 18-49, 10.2 million viewers overall), and in adults 18-49 it finished a tick behind ABC’s “Castle” head-to-head in the 10:30 half-hour. “Smash” saw its most troubling decline in the second half-hour to date, dropping 26% from a 2.7 rating at 10 p.m. to a 2.0 at 10:30.

Still, NBC comfortably led the night in 18-49 (by 2 shares over CBS) and also prevailing in 25-54 and total viewers.

CBS saw leadoff hitter “How I Met Your Mother” (3.8/10 in 18-49, 9.8 million viewers overall) bounce back 12% from its season low of last week, and enabled “2 Broke Girls” (4.0/10 in 18-49, 11.3 million viewers overall) and “Two and a Half Men” (4.1/10 in 18-49, 13.2 million viewers overall) to grow some as well; they and steady 9:30 p.m. sophomore “Mike & Molly” (3.4/8 in 18-49, 11.3 million viewers overall) were the night’s strongest counter to “The Voice” in each half-hour from 8 to 10. And at 10, “Hawaii Five-0” edged up to win its hour across the board.

ABC’s two-hour “The Bachelor” held steady (2.5/6 in 18-49, 8.1 million viewers overall), and “Castle” (2.1/5 in 18-49, 9.7 million viewers overall) inched up to finish close behind “Smash” in 18-49 while beating the NBC rookie in 25-54 and total viewers.

Fox’s drama tandem of “House” (2.3/6 in 18-49, 7.0 million viewers overall) and “Alcatraz” (1.8/4 in 18-49, 6.0 million viewers overall) fell a bit more this week, with the latter’s prospects for a second season looking rather bleak at this point.

And at CW, “Gossip Girl” (0.5/1 in 18-49, 1.0 million viewers overall) and “Hart of Dixie” (0.6/1 in 18-49, 1.5 million viewers overall) matched their week-ago deliveries, with the latter building on its vet’s lead-in among adults 18-34 (0.7 vs. 0.5).

Preliminary 18-49 averages for the night: NBC, 4.6/11; CBS, 3.5/9; ABC, 2.4/6; Fox, 2.1/5; Univision, 1.5/4; CW, 0.5/1.

In total viewers: NBC, 12.6 million; CBS, 11.0 million; ABC, 8.6 million; Fox, 6.5 million; Univision, 3.8 million; CW, 1.2 million.